Microwave Cooking
Just like the radio waves, microwaves are electromagnetic waves having very high frequency but in contrast to radio waves they have short wave lengths. To understand the difference, while the radio waves may have a length starting from three feet to a few miles, the microwave length is around 3 inches long. Because of their short length and the design of the oven they remain inside the oven. The oven consists of a magnetron unit that generates the microwaves, which are then sent to the metallic hollow of the oven normally from an opening at the upper side.
Since the microwaves sent to the hollow is made of metal they are not able to move out of the cavity and keep getting collected there. This generates a lot of energy. The food kept inside the oven during this process gets cooked using this energy. It is important that the oven is not empty while the waves are collected there because if the energy generated does not get consumed, it will damage the system. For even distribution of energy at the time of microwave cooking the oven has a fan with in.
Microwave cooking is said to be safe and at the same time very fast. However, not all the dishes can be prepared using microwave oven. But great results have observed once you have the knowledge of cooking the common foods.
It is interesting to learn that the microwaves that cannot pass thru the metal can actually penetrate thru other materials like paper, plastic, glass and pottery. It is therefore recommended to use utensils made out of these materials instead of those made of metal. Even if the utensils made of these materials contain some amount of metal they should be avoided. It is however good to use the guidelines from the booklets that come along with the device to help us learn about operating it properly.
To understand the technique used you first need to understand that microwave cooking does not do it by heat radiation or heat transfer instead it uses the concept of friction. Friction is generated in the water molecules with in the food by randomly orienting them. Using the theory of unlike poles attracting each other, the hydrogen atoms with positive charge move towards the negative end and the oxygen atoms with negative charge move towards positive end. But since the polarity of the field changes continuously, it creates a random atmosphere. The friction that takes place by the random movement of the oxygen and hydrogen molecules generates heat, which is used to cook the food.
Since there are no chemical changes taking place in the food it does not loose any of its natural contents and hence it is good for health. Also the food is heated evenly from all the sided up to ¾ to 1 ½ inches. Once the outer area of the food is cooked the heat generated gets transferred to the inner parts and that also gets cooked. One of the good techniques to ensure even cooking in the oven is to arrange the food in such a way that there is some empty space left in the middle area of the dish.